Display System, Display Method in the System and Display Program for Using Social Graph Information of Users of Multiple Applications

1. A system comprising: circuitry configured to for each of a plurality of application programs, store relational information indicating a relationship between a plurality of users, each identified by a user identifier; in response to a request by a first user of the plurality of users from a first application program of the plurality of application programs, extract, for each of the plurality of application programs, one or more user identifiers of one or more users, in which the relationship between a user and the first user meets a predetermined condition based on the relational information; output the extracted one or more user identifiers to the first application program; and cause information corresponding to the extracted one or more user identifiers to be displayed on a client terminal of the first user, wherein the information is displayed such that one or more application programs of the plurality of application programs, in which the relationship between the user corresponding to the user identifier and the first user meets the predetermined condition, are identified, and the information is displayed simultaneously with an indication of the relationship between the user corresponding to the user identifier and the first user, in a descending order of a number of the one or more application programs on a same screen.

2. The system according to claim 1 , wherein the circuitry is configured to cause the information corresponding to each of the extracted one or more user identifiers to be displayed such that the information is displayed in association with the one or more application programs of the plurality of application programs, in which the relationship between the user corresponding to the user identifier and the first user meets the predetermined condition.

3. The system according to claim 1 , wherein the circuitry is configured to extract at least one user identifier by executing an application program interface (API) program of the plurality of application programs.

4. The system according to claim 1 , wherein the relational information includes relationship value information.

5. The system of claim 4 , wherein the circuitry is configured to combine and normalize the relationship value information regarding the application programs for each user of the plurality of users.

6. The system of claim 5 , wherein the circuitry is configured to extract a user identifier of at least one user meeting the predetermined condition based on the normalized relationship value information included in the relational information.

7. The system of claim 1 , wherein the system is a plurality of servers connected via a network.

8. The system of claim 1 , wherein the relational information includes information indicating friend relationships between the plurality of users.

9. The system of claim 1 , wherein the circuitry is configured to transmit, to a client terminal of a second user corresponding to one of the extracted one or more user identifiers, an invitation to establish a relationship between the first user and the second user in the first application program.

10. The system according to claim 1 , wherein the relationship between the user corresponding to the user identifier and the first user meets the predetermined condition in two or more application programs of the plurality of application programs, and the information is displayed in a descending order of a number of the two or more application programs.

11. The system according to claim 1 , wherein each of the plurality of application programs corresponds to application software.

12. A method performed by a system, the method comprising: for each of a plurality of application programs, storing relational information indicating a relationship between a plurality of users, each identified by a user identifier; in response to a request by a first user of the plurality of users from a first application program of the plurality of application programs, extracting, for each of the plurality of application programs, one or more user identifiers of one or more users, in which the relationship between a user and the first user meets a predetermined condition based on the relational information; outputting the extracted one or more user identifiers to the first application program; and causing information corresponding to the extracted one or more user identifiers to be displayed on a client terminal of the first user, wherein the information is displayed such that one or more application programs of the plurality of application programs, in which the relationship between the user corresponding to the user identifier and the first user meets the predetermined condition, are identified, and the information is displayed simultaneously with an indication of the relationship between the user corresponding to the user identifier and the first user, in a descending order of a number of the one or more application programs on a same screen.

13. A non-transitory computer readable medium including a program, which when executed by a circuitry of a system, causes the circuitry to: for each of a plurality of application programs, store relational information indicating a relationship between a plurality of users, each identified by a user identifier; in response to a request by a first user of the plurality of users from a first application program of the plurality of application programs, extract, for each of the plurality of application programs, one or more user identifiers of one or more users, in which the relationship between a user and the first user meets a predetermined condition based on the relational information; output the extracted one or more user identifiers to the first application program; and cause information corresponding to the extracted one or more user identifiers to be displayed on a client terminal of the first user, wherein the information is displayed such that one or more application programs of the plurality of application programs, in which the relationship between the user corresponding to the user identifier and the first user meets the predetermined condition, are identified, and the information simultaneously with an indication of the relationship between the user corresponding to the user identifier and the first user, is displayed in a descending order of a number of the one or more application programs on a same screen.